Forced draft gas burner



April 29, 1952 J. H. JACKSON FORCED DRAFT GAS BURNER 2 SHEETS- SHEET l Filed Aug. 4, 1949 April 29, 1952 J. H. JACKSON FORCED' DRAFT GAS BURNER 2 SHEETS-SHEET 2 Filed Aug. 4, 1949 Patented Apr. 29, 1952 VUNITED STATES PATENT OFFICE 12,594,562 'FORCED DRAFT GAS BURNER James H. Jackson, Detroit, Mich.

Application August4j, 1K949, Serial No. 108,600

e claims. (ci. 15s- 99) This invention relates to 'fuel burners `and. in particular, to gas burners. l

'One object of this invention isto provide a power-driven or forced draft gas burner whichis capable of burning either natural gas, manufactured gas or mixtures of gases, as well as bottled gas,A such as propane or butane gas, in an eiiicient and economical manner.

Another object is to provide a forced draft gas burner wherein the air blast and the gas are eici'ently and accurately mixed and regulated so that efficient combustion and an extremely hot flame are produced.

Another object is to provide a forced draft gas burner which is capable Aof being mounted in domestic heating furnaces and which will safely meet all the Arequirements of such furnaces in domestic and industrial heating.

Another object is to provide a forced draft gas burner having an improved safety device inthe form of an air blast actuated switch for insuring thatno l'gas will be admitted to the burner until or unless 'the air is flowing in sufficient volume into the air `mixing chamber and thence to the gasijet. Q

In the drawings:

Figure l1`is 'a side elevation, partly in central vertical Vsection, through a forced draft gas burner according to oneform of the invention;

Figure 2 'is 'a top plan view, partly in horizontal section, of the gas burner shown in Figure 1;

Figure' 3 is a horizontal section taken along the line 3-13 in Figurel showing the air swirling vanes;

Figure 4 isa cross-section taken along vthe line 4 4 in Figure'l showing the'twin channeled vair conduit with its regulating damper; and

Figure 5 :is a cross-section .taken along the line 5-5 inlFi'gure 2, showing thersafety switchmechanism.

Referring'to `the drawings generally, Figure 1 shows a 'forced draft or power-driven gas burner, generally designated I0, as consisting generally of 'a blower unit I I connected to the inlet conduit I2 of an airmixing chamber I3 by way of an'airresponsive Vsafety switch .mechanism .I 4. Mounted lon the lair mixing chamber 'I3 is a spirally varied-blast tube I 5 surmount'ed by a hollow tubular trumpet-shaped hearth I6 which in turn is surmounted by an oppositely-shaped baiiie I'I. The latter carries an upper gas jet I8 which is threaded `into a lower gas jet I9 supplied with gas by a` gas supply pipe 20. Apilot burner 2l ignites the combustiblemixture of Vgas andair emerging throughzthe annular gap between lthe baffle I'I- and hearth I6. The air mixing chamber I3 and blast tubel infassembly constitute an air container on Awhich thehearth I6 is mounted.

yReferring to thedrawings in detai1,*-the blower4 unit II consists of a volute casing 22 (Figures '.1

'V and 2') with a central airinlet port 23 and a tan- `:plied thereto until a ysufficiently strong blast of.

gential outlet 'conduit 24 which is flanged as at and bolted as at 26 tothe flanged portion-21 on the shaft '29 of a blower motor 30, the latter being flanged-as at 3| and bolted as at 32 tothe side wall of the casing 22.

'In order to insure safe operation of the gas burner I0 and to prevent any gas from being supair is being delivered from the vblower II, the airresponsive safety switch I4 is provided atapprox-l imately a junction between the blower I I and airv mixing chamber I3. In particular. a bent l bracket33 is isecuredas at 34 tothe flange 25 and near its outer end carries a normally open switch 35' having an operating Vplunger `36 and wires 31 and 3B leading to the control circuit of an electromagnetically operated gas supply valve (not shown) which is interposed between 'the gasma'in and the gas supply Ypipe 20. The electro-magnetic valve vforms a part of a gas manifold assembly'(not shown) 'which is'ccnventional and which in vits details is beyond the scope of the 'present invention.

on the pivot pin v42 is a sail arm or `lever 43,` the 1 theA end of the arm43 is -a sail disc 46.

end portion of 'which is flattened to engage the switch plunger 36 'and to fit between the ears'lll. The opposite end portion'passes through -a hole 44 in the outlet :conduit 24. Secured asiat 45to Consequently, when the blower II `*is-operatingV so asto force a blast of air through the discharge conduit 24, thisvblast engages the sail disc 46 and swings the sail arm 43 to the right (Figure 2), closing the normally open-switch 35 and therefore closing the circuit to thelelectromagnetic gas valve (not shown). When, however, the blower II is not operating and no air is flowing throughvtheoutlet conduit 24, theiusual spring (not shown) withv in the'switch135 urges'the` plunger 36 outward .and

consequently swings the y-arm 43 andr sail.disc.j46 to the left (Figure 2).

The air mixing ichamber I3 rand its inlet-conduit I2 `are ofthe type' Adisclosedfand claimed in the Jackson PatentNo. 2,420,598 of May 13, 1947 for Liquid Fuel Burner, and its details are 'beyond the scope-of :the ypresent invention. vvFor the `purposes of the present disclosurepthe air.

inlet conduit I2 is provided with a central internal A.partition 41 (Figure .4) dividing the inthreaded studs 53 (Figure 1) which in turn are threaded into legs 54 resting uponl a suitable supporting surface 55 within the furnace.

The top of the air mixing chamber casing 52 is open, and is provided with an' upwardly-projecting conical iianger 56 which telescopes-with the baille I1 and threaded as at 83 into the threaded upper end of the bore 19. The baiile I1 is provided with a series of downwardly projecting lugs 84 (Figure 1) which rest upon the upper surface of the anged portion 68 of the hearth I6 and thereby determines the width of the opening therebetween. The inner surface 85 of the-hearth I6 and the outer surface 86 of the baie I1 are both of trumpet-shaped or arcuate cross-section, and are spaced apart from one another toprovide an approximately annular upwardly andoutwardly flaring passageway 81 .whic'hleadsfrom the outlet opening 88 of the air mixing chamber casing 52 and the blast tube a downwardly projecting conical iiange 51 upon the lower end of the-Y blast tube I5. Mounted within the blast tube I5 near the-upperA end thereof are multiple spiral vanes 58 preferably castintegral with the blast tube l5 and serving to direct thev air in a swirling or vortex path as it moves upward through the blast tube I5 (Fig-l ures 1 and 3). the blast tube If5 is the annular shouldered groove or counterbore 59 within the lower end of the trumpet-shaped hearth I6. The hearth I6 fiares upward and outward to provide a trumpet-shaped cavity and terminates in a flange 60 at its upper edge (Figure 1). Secured as at 6I Vto the flange 68 is a bracket 62 on which a conventional pilot burner 63 is mounted, andl whichis supplied with gas from a pilot burnerA supply pipe 64. Mounted on the arm projecting from the pilot burner 83 is a thermostat l65 to which is connected the conduit 68 which leads to the'control circuit and which also servesto cut off the gas supply in a known manner in case` the pilot burner 63 should become extinguished or fail to ignite.

The bottom wall of the air mixing chamber casing 52 is provided with a central opening 61 in which is mounted the flanged lower portion 68 ofthe upstanding lower gas jet 69 and securedv thereto as at 10. The gas supply pipe`20 is threaded into the threaded port 1I at the lower end of the lower jet 69' (Figure 1) and supplies gas thereto. The lower gas jet89 near its upper end is provided with an outwardly flaring conical portion 12, and a gas passageway or bore 13 extends upward .from the threaded port 1I through the flared portion 12 and terminates at its upper end in a threaded portion 14. The flared conical portion 12 vof the lower jet I9 thus projects toward the blast tube I5 and forms a constriction in the blast tube I5. This causes an acceleration in the speed of the air passing therethrough, as a result of the Venturi effect created by this constriction, the annular a'ir passageway between the flared portion 12 and the blast tube I5 widening immediately above the upper end 11 of the flared portion 12. Threaded into thefthreaded portion 14 is a correspondingly threaded portion 15 on the tubular upper gas jet I8, and extending downward below the threaded portion 15 is a skirt 16. Above the upper end 11 of the lower jet I9 the upper jet I8 is provided with a multiciplicity of radial gas ports 18 extending through its side walls from its internal bore 19 (Figure 1).

' The upper portion of the upper gas `iet i8 is.v

seated'in a borev or socket 88 formed in the lower end of the trumpet-shaped baifie I1 (Figure 1) and is held in place by a bolt or cap screw 8| passing downward through a central bore 82 in Resting on the upperv edge of through the inlet opening 23 (Figure 2) and dis-.-

` 'passageway 89'tol the upper annular outlet gap 90;.he'tw'ee'n the iiange 9I of the baffle I1 and the flange 68 of the hearthIG.

lnfvtmhe operation of the gas burner of this invention, let it be assumed that the'burer IIlh'as been Vset up in la suitable furnace and that the' gas supply pipes 20 and I(i4 have been connected, to a source of gas such as natural gas, manufactured` gas, vbutane, propane or'the like,rand that the motor 38 has been energized from a suitable electricalY circuit. When the motor 30i is vstarted in operation, a blast of air is drawn in charged through the air passageway 92 within the discharge conduit. 24 into the passageways- 48 and 49 (Figures 2 and 4) within the intake conduit I2 of the air mixing chamber I3. The proportionate ldistribution of the air between the two channels or passageways 48 and 49 is regulated by adjusting screw 5I against the damper 50.

The air blast,rthus divided bythe partition'. 41, emerges from the channels or passageways 48 and 49 into diametrically opposite portions4 of the air chamber 93 within the air mixingy chamber casing 52, and thereby has acquired a swirling motion which continues as the air passes upward through the opening 88 and passage 89 within the blast tube I 5. Here it encounters the spiral vanes 58, which further increases the vortex motion of the air.'v At the upper ends of the vanes 58 it encounters the streams of gas emerging radially from the ports 18 of the upper gas jet I8, the gas having passed upward from the supply pipe 20 through the bore 13 of the lower jet I9 to reach the upper jet I8. The gas mixes with the swirling air in the upwardly and outwardly flaring passageways 81 and the combustible mixture emerges through the annular-gap 98 (Figure 1) where it is ignited byv the pilot burner 63. The name shoots outward and'then upward from the edge oi the baie I1 and heats the interior of the furnace in the I, usual Way.

'The amount of gas reaching the mixing passageway 81 is regulated by the size and number of ports 18 in the upper gas jet I8, whereas the velocity of the gas release is regulated by the lower annular gap 94 between the lower jet I9 and the lower end of the baie I1. The volume or rate of iiow of the combustible mixture of air' and gas is regulated by the upper annular gap 9D which in turn is regulated by the lengths of the` lugs 84.

urges the switch plunger 3B outward then does so, opening the switch 35 and consequently opening the safety circuit which closes the electromagnetic gas supply valve (not shown). This terminates the flow of gas through the gas supply pipe 20 and pilot burner supply pipe 64.

What I claim is:

l. A forced draft gas burner comprising an air container having an upwardly directed air conduit connected thereto, a power-driven air blower having its discharge connected to said air container, a hollow hearth structure connected to said air conduit and having an upwardiy directed cavity therein communicating with said air con duit, a gas jet device including a gas conduit disposed within said air conduit and defining an annular air passageway therebetween having its outlet discharging outwardly into said cavity, and a baffle structure mounted over said cavity in spaced relationship therewith and having a peripheral burner gap therebetween.

2. A forced draft gas burner comprising an air container having an upwardly directed air conduit connected thereto, a power-driven air blower having its discharge connected to said air container, a hollow hearth structure connected to said air conduit and having an upwardly directed cavity therein communicating with said air conduit, a gas jet device including a gas conduit disposed within said air conduit and denning an annular air passageway therebetween having its outlet discharging outwardly into said cavity, and a baiile structure mounted over said cavity in spaced relationship therewith and having a peripheral burner gap therebetween, one of said conduits having an annular portion projecting toward the other conduit and forming a constriction in said air passageway, said cavity above said constriction being wider than said constriction whereby to provide a venturi effect causing an acceleration of the speed of the air passing therethrough.

3. A forced draft gas burner comprising an air container having an upwardly directed air conduit connected thereto, a power-driven air blower having its discharge connected to said air container, a hollow hearth structure connected to said air conduit and having an upwardly directed cavity therein communicating with said air conduit, a gas jet device including a gas conduit disposed within said air conduit and defining an annular air passageway therebetween having its outlet discharging outwardly into said cavity, a bailie structure mounted over said cavity in spaced relationship therewith and having a peripheral burner gap therebetween, and a multiplicity of inclined air directing vanes disposed within said annular air passageway.

4. A forced draft gasburner comprising an air container having an upwardly directed air conduit connected thereto. a power-driven air blower having its discharge connected to said air container, a hollow hearth structure connected to said air conduit and having an upwardly directed cavity therein communicating with said air conduit, a gas jet device including a gas conduit disposed within said air conduit and defining an annular air passageway therebetween having its outlet discharging outwardly into said cavity, a baiiie structure mounted over said cavity in spaced relationship therewith and having a peripheral burner gap therebetween, one of said conduits having an annular portion projecting toward the other conduit and forming a constriction in said air passageway, said cavity above said constriction being wider than said constriction whereby to provide a venturi eiect causing an acceleration of the speed of the air passing therethrough, and a multiplicity of inclined air directing vanes disposed in said constriction in said annular air passageway and adjacent said hearth structure.

5. A forced draft gas burner comprising an air container having an upwardly directed air conduit connected thereto, a power-driven air blower having its discharge connected to said air container, a hollow hearth structure connected to said air conduit and having an upwardly directed cavity therein communicating with said air conduit, a gas jet device including a gas conduit disposed within said air conduit and dening an annular air passageway therebetween having its outlet discharging outwardly into said cavity, a baille structure mounted over said cavity in spaced relationship therewith and having a peripheral burner gap therebetween, one of said conduits having an annular portion projecting toward the other conduit and forming a constriction in said air passageway, said cavity above said constriction being wider than said constriction whereby to provide a venturi effect causing an acceleration of the speed of the air passing therethrough, and a multiplicity of inclined air directing vanes disposed in said constriction in said annular air passageway and adjacent said hearth structure and terminating adjacent said jet device outlet.

6. A forced draft gas burner comprising an air container having an upwardly directed air conduit connected thereto, a power-driven air blower having its discharge connected to said air container, a hollow hearth structure connected to said air conduit and having an upwardly directed cavity therein communicating with said air conduit, a gas iet device including a gas conduit disposed within said air conduit and denning an annular air passageway therebetween having its outlet discharging outwardly into said cavity, and a baille structure mounted over said cavity in spaced relationship therewith and having a peripheral burner gap therebetween, said hearth structure cavity being of concave trumpet-shaped configuration with a substantially horizontal internal peripheral surface and said baffle structure having a portion of convex trumpet-shaped configuration projecting into said cavity in spaced relationship therewith and having a substantially horizontal internal peripheral surface spaced above and facing said hearth structure internal peripheral surface.

JAIVIES H. JACKSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 621,968 Kurtz Mar. 28, 1899 1,567,830 Blanchard Dec. 29, 1925 1,636,140 Maehler July 19, 1927 1,898,799 Wetherbee Feb. 21, 1933 2,159,658 I-Iall May 23, 1939 2,214,912 Valjean Sept. 17, 1940 2,220,572 Knupp Nov. 5, 1940 2,230,826 Burdett et al Feb. 4, 1941 2,504,451 Richeson Apr. 18, 1950 

